The present research deals with the regulation of microtubule assembly. We are studying the mechanism of nucleotide function in tubulin assembly; the role of accessory proteins such as tau protein, and the role of rings and other oligometric forms of tubulin. Other studies in this laboratory concern tubulin assembly in cultured CHO cells. We are also concerned with nucleated microtubule assembly and polarity of growth as well as structural and functional studies of centrioles utilizing microinjection into Xenopus eggs. BIBLIOGRAPHIC REFERENCES: Weingarten, M.D., Lockwood, A.H., Hwo, S.-Y. and Kirschner, M.W., A Protein Factor Essential for Microtubule Assembly, Proc. Nat. Acad. Sci. U.S. 72, 1857 (1975). Heidemann, S. and Kirschner, M.W., Aster Formation in Eggs of Xenopus laevis: Induction by Isolated Basal Bodies, J. of Cell Biol., 67, 105 (1975).